Cut over-engineering found by a repo-wide audit

- Config: auth, services, logging, queue and database only repeated the
  framework's own files and are gone; the others keep only the keys that
  differ (app version, cache serializable_classes, session cookie name,
  Markdown mail theme, the shares disk, three Octane values, Livewire's
  pagination theme and payload guards).
- Email verification is removed: User never implemented MustVerifyEmail,
  so it was never enforced, and SealShare has a single admin and no
  registration. CreateNewUser goes with it.
- FileEncryptionService::encryptFile() and generateSalt() were only used
  by tests; tests build files with encryptTestFile() in tests/Pest.php.
- The expiration options are defined once, as Share::EXPIRATIONS. "30 Days"
  now lasts 30 days instead of a calendar month, and Admin settings only
  save a default expiration that is one of the options.
- One-caller helpers are inlined, the uploader reads chunk responses with
  XHR's responseType, and starter-kit leftovers are removed.
- Docker: PHP reads the PHP_* limits from the environment itself
  (${VAR:-default} in uploads.ini); both entrypoints stop writing the ini.
  docker-compose.yml shares the app and scheduler variables through one
  anchor. The dev image installs gd for the screenshot publisher and fake
  test images.
- Development runs in Docker only: the composer dev script, concurrently,
  laravel/pail, laravel/sail, autoprefixer and the shell-quote override
  are gone.
- phpunit.xml forces the test environment with <server> entries, so tests
  run in the dev container no longer use its real database.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tests/Feature/FileUploadTest.php

@@ -249,6 +249,21 @@ test('file upload with expiration sets expires_at', function () {
     expect($share->expires_at)->not->toBeNull();
 });
 
+test('a 30 day expiration lasts 30 days, not a calendar month', function () {
+    Storage::fake('shares');
+    $this->travelTo(new DateTimeImmutable('2026-02-01 12:00:00'));
+
+    $component = Livewire::test(FileUploader::class);
+    uploadThroughPage($component, ['file.txt' => 'content']);
+
+    $component
+        ->set('expiration', '30d')
+        ->call('createShare')
+        ->assertRedirectContains('/share/');
+
+    expect(Share::query()->first()->expires_at->toDateTimeString())->toBe('2026-03-03 12:00:00');
+});
+
 test('file upload with max downloads sets limit', function () {
     Storage::fake('shares');